The National Institute of Standards and Technology (NIST) has achieved a new world record for the most accurate clock, with its aluminum ion clock now capable of measuring time to the 19th decimal place.

As a result of 20 years of ongoing development, the NIST has created a “quantum logic clock” that utilizes a pair of aluminum and magnesium ions and quantum computing.

The quantum logic clock’s accuracy is 41% greater than the previous record, and it’s also 2.6 times more stable than any other ion clock, according to the NIST. Being able to define the second, with a new level of precision, will enable new scientific and technological advances.

Optical atomic clocks are typically judged by two measures: accuracy and stability. Accuracy, in this context, means how close a clock comes to measuring the ideal “true” time, which is also known as systematic uncertainty. Stability, or how efficiently a clock can measure time, is related to its statistical uncertainty.

In order to achieve this new timekeeping benchmark, a number of advancements had to be made.

First, the research group paired an aluminum ion with magnesium, which allowed them to realize the beneficial ticking properties of aluminum and the ability to control the magnesium with lasers. “This ‘buddy system’ for ions is called quantum logic spectroscopy,” said Willa Arthur-Dworschack, a graduate student on the project.

Second, a key factor in achieving this level of accuracy was redesigning the ion trap to minimize “excess micromotion,” which are tiny, unwanted movements of the ions that can affect the clock’s precision, according to NIST. 

Third, the vacuum chamber was upgraded to reduce background hydrogen gas, which can interfere with the ions. The chamber was rebuilt with titanium, resulting in a 150-fold reduction in hydrogen gas, according to NIST.

Finally, the new aluminum ion (atomic) clock contributes to the ongoing international effort to redefine the second with greater accuracy, which could lead to significant advancements in science and technology.

Read the full article on the NIST website.

Photo of modified ion trap for the aluminum ion clock by R. Jacobson/NIST.